Switch sigpending over to rt_sigpending.

Change-Id: I7b28984796b5fb343cfbcc47e0afc3a84293d417
diff --git a/libc/arch-x86_64/syscalls.mk b/libc/arch-x86_64/syscalls.mk
index 6b72ca0..611bb35 100644
--- a/libc/arch-x86_64/syscalls.mk
+++ b/libc/arch-x86_64/syscalls.mk
@@ -3,9 +3,9 @@
 syscall_src += arch-x86_64/syscalls/_exit.S
 syscall_src += arch-x86_64/syscalls/_exit_thread.S
 syscall_src += arch-x86_64/syscalls/__fork.S
-syscall_src += arch-x86_64/syscalls/__waitid.S
 syscall_src += arch-x86_64/syscalls/wait4.S
 syscall_src += arch-x86_64/syscalls/__sys_clone.S
+syscall_src += arch-x86_64/syscalls/__waitid.S
 syscall_src += arch-x86_64/syscalls/execve.S
 syscall_src += arch-x86_64/syscalls/getuid.S
 syscall_src += arch-x86_64/syscalls/getgid.S
@@ -150,6 +150,7 @@
 syscall_src += arch-x86_64/syscalls/timerfd_settime.S
 syscall_src += arch-x86_64/syscalls/timerfd_gettime.S
 syscall_src += arch-x86_64/syscalls/__rt_sigaction.S
+syscall_src += arch-x86_64/syscalls/__rt_sigpending.S
 syscall_src += arch-x86_64/syscalls/__rt_sigprocmask.S
 syscall_src += arch-x86_64/syscalls/__rt_sigsuspend.S
 syscall_src += arch-x86_64/syscalls/__rt_sigtimedwait.S
diff --git a/libc/arch-x86_64/syscalls/__rt_sigpending.S b/libc/arch-x86_64/syscalls/__rt_sigpending.S
new file mode 100644
index 0000000..ecf1971
--- /dev/null
+++ b/libc/arch-x86_64/syscalls/__rt_sigpending.S
@@ -0,0 +1,17 @@
+/* autogenerated by gensyscalls.py */
+#include <asm/unistd.h>
+#include <linux/err.h>
+#include <machine/asm.h>
+
+ENTRY(__rt_sigpending)
+    movl    $__NR_rt_sigpending, %eax
+    syscall
+    cmpq    $-MAX_ERRNO, %rax
+    jb      1f
+    negl    %eax
+    movl    %eax, %edi
+    call    __set_errno
+    orq     $-1, %rax
+1:
+    ret
+END(__rt_sigpending)